Sky's Chris Froome had his first truly straightforward day as race leader yesterday as a break of 18, including Britain's David Millar, fought it out for the stage win – taken by Italy's Matteo Trentin – while the overall contenders eased back.

Surrounded by a phalanx of Sky team-mates, Froome rolled across the line in 22nd place, with his 2min 28sec lead over Holland's Bauke Mollema intact. During the 191km hilly stage to Lyon, for once the Briton was never under threat.

Looking ahead to today's crucial stage up the singularly hard Mont Ventoux, Froome was cautious about his chances, pointing out that he is fighting for a longer-term goal – winning in Paris overall – rather than risking everything for a possibly Pyrrhic victory on "the Bald Mountain" that might deplete his energy for the final week.

"Winning [there] would be a dream come true, but I'm sure that a lot of people will want to win it," Froome said cautiously, "I'm not the only one aiming for that."

Asked if he was looking forward to racing there for the first time, Froome responded with a smile: "A rest day would be nice. Instead we've got the Mont Ventoux, and after nearly 250 kilometres of riding" – the longest stage of the Tour – "it's going to be really hard.

"I have ridden up there, I know what's coming. It's one of the most difficult climbs out there. It'll take us about an hour to climb and it'll be a really epic day."

Froome and Team Sky had a much more structured stage yesterday as a break of 18 riders, none of them an overall threat, went clear with around 100km to go.

British fans had hopes that Millar might be able to repeat his solo stage win of 2012. He chanced his arm with a long-distance attack from the break around 25km to go, and when that failed was quickly dropped, indicating with a "cut-throat" gesture that he was completely exhausted.

France's Julien Simon soared away on a late ascent, opening up a gap of 12 seconds. But he was finally swept up by a dozen riders. Instead Italy's Matteo Trentin, a team-mate of Mark Cavendish, claimed the Belgian Omega Pharma-Quickstep squad's fourth stage win, and their second in as many days.

Today's stage

The assault of the 21km Mont Ventoux, one of France's most emblematic and toughest climbs, will either see Chris Froome reassert Sky's authority in the race with his second mountaintop stage win, or leave everything to play for in the final week in the Alps.